(19)

(11)

EP 0 397 771 A1

(12)

(43) Date of publication: 22.11.1990 Bulletin 1990/47 (21) Application number: 89902272.0 (22) Date of filing: 06.02.1989

(51) International Patent Classification (IPC):  E21B 34/ 04( . ) E21B 41/ 04( . ) (86) International application number: PCT/GB1989/000101 (87) International publication number: WO 1989/007191 (10.08.1989 Gazette 1989/18)

(84) Designated Contracting States: FR GB (30) Priority: 06.02.1988 GB 19880002737 22.08.1988 GB 19880019910 (71) Applicants: MOBIL OIL CORPORATION New York New York 10017 (US) FSSL LIMITED Aberdeenshire AB4 9RF (GB) CAMERON OFFSHORE ENGINEERING LIMITED Surrey GU21 1DG (GB)	(72) Inventors: HOPE, Rodney, Charles Southampton Hampshire (GB) LAWSON, John Ernest Woking Surrey, GU21 4LW (GB) HATTON, Stephen Anthony Woking Surrey, GU22 9BQ (GB) (74) Representative: Jones, Alan John  CARPMAELS & RANSFORD 43 Bloomsbury Square London, WC1A 2RA London, WC1A 2RA (GB)